TFT-LCD (Thin Film Transistor Liquid Crystal Display) is configured such that a glass substrate having a TFT array and a glass substrate having a color filter are layered at a predetermined interval, and liquid crystals are injected between these two glass substrates to form a panel, to which an electrical signal is then applied, to render a display.
Such LCDs may be classified into reflective, transmissive and transflective types depending on the source of the backlight. A reflective LCD reflects an external light source and uses it as a backlight so that a predetermined reflective sheet is required, whereas a transmissive LCD uses an internal light source as a backlight, namely, uses the light of a backlight unit itself.
A transflective LCD is in the form of a combination of the reflective LCD and the transmissive LCD and uses both the external light source and the internal light source. Because the transflective LCD is provided with both a reflective sheet and a backlight unit, external light reflected by the reflective sheet is used on the one hand and internal light emitted from the backlight unit is used on the other hand.
In the case where the brightness of the LCD is not higher than the peripheral luminous intensity, display performance may decrease due to a difference in contrast ratio. To solve this problem, there are methods of partially using external light by means of a transflective LCD and of increasing the luminance of a transmissive LCD itself. The transflective LCD is advantageous because luminance may increase using external light under bright conditions, but is problematic in that reflective cells which operate in a reflective mode constitute 50% of the total opening area and the efficiency is very low to the extent of less than 5% in a reflective mode, undesirably lowering brightness under dark conditions.
Furthermore, because the properties of external light are different from those of internal light, the difference therebetween has to be controlled over time.
In addition, the method of increasing the luminance of the transmissive LCD itself is illustrated. In this case, power consumption may increase because of using a high-luminance backlight in order to obtain high luminance.
Recently, methods of increasing the transmittance of an internal light source using white pixels have been devised. These methods are advantageous in terms of increasing luminance, but resolution may decrease due to the use of white pixels, and also additional imaging processes are required.
Therefore there is a need to develop a transflective LCD which may sufficiently utilize external light without decreasing resolution, and thus the development of a photosensitive resin composition which facilitates the formation of a pattern is urgently required.